The primary goal of this acute, inpatient treatment protocol is to compare the putative, short-term benefit of the most selective and highly potent serotonin reuptake inhibitor (citalopram) and our usual pharmacotherapy (perphenazine) with placebo in reducing behavioral disturbances and/or psychosis associated with dementia. In addition, precise drug metabolic probes are used to identify those at risk of adverse psychotropic side effects.